Means for varying the voltage ratio of transformers.



No. 740,154. PATBNTBD sBPT.2s,1soa.

MEANS `FOR VARYINGTHE VOLTAGE RATIO 0F TRANSFORMBBS. nrmonxox nun rn. 2|. 1m.

E191. Ely@ l0 KODBL.'

UNiTED STATES Patented September '29, 1903.V

PATENT OFFICE. j

JOHN S. PB CK, F PITTSBURG, PENNSYLVANIA, ASSIGNOR TO TESTING- IIOUSF. l'lLlCTRlC d: MANUFACTURING COMPANY, A CORPO-RATION OF rnXNsviA-'Ams l MEANS FOR VARYI'NG THE VOLTAGE' RATIO-.OF TRA'NSFORMERSI'.

SPECIFICATION forming part of Lettori Patent No. 740,174, dntl'i September 29, 1903. Application Sled February 28, 1903. Snrixl No. 146.619. (No model.)

To all whoml it muy concern:

lie it known that I, JOHN S. PECK, a citizen ofthe United States,'residing in Pittsburg, in

the county of Allegheny and State of Penn- Sylvania, have invented a new and useful lmprovcincnt in Means for Varying the Voltage Ratio of Transformers, of which the-following is a specification.

My invention relatesto transformers, and specially to means for varying the voltage ratio of transformers.

The object of my invention is to provide a simple and efficient means whereby the active lengthof either the primary or the secondary winding of a transformer may be varied to snit the ratio of transformation without materiallyaltering the balanced condition ofthe several parts of the windings, which obtains when the entire lengths of both windings are in circ'lit.

lt is frequently desired to change the voltage ratio of n transformer by changingr the number of turns inthe one or the other of its windings. This is ordinarilyaccomplished by providing taps or leads from different points in one of the windings and Vtransferring one line-terminal from one tap or leadv to another by means of a snitable regulator or switching device.

Nearly all transformers of anyconsi'derable size are provided with several primary and several secondary coils, which are so interlaced in the transformer that the magnetic leakage is a minimum, and if the coils of either winding are to be connected in parallel it is necessary that each-of the coils shall occupy a symmetrical magnetic position with reference to the coils of the opposite winding, for the reas'on that if the positions are nnsyminetrical the voltages induced in the different coils will be diierent and when connected in parallel there will be an interchange of 'cnrrcnt between the coils, which will be productive of heat to an objectionable degree. It follows, therefore, that with the usual arrangement above mentioned the cutting.ont of some of the turns of the primary winding, forexample, will leavethe secondary coils '-.insymmetrieallylocated with refer 5e ence to the active primary winding, and when so located they cannot be connected ir. pan nllel with each other-without an interchange of current, which causes heat.

I have shown in the accompanying drawings means for avoiding the ditiicnlties here inbefore pointcd'ont, in whch- Figure 1 is a diagram of a transformer and regnlatorcenstructed and arranged in accordance withl my invention, and Figs. 2, 3, and 1 are simi-lar views of modification-s.

In Fig. 1 I have shown a transformer 1, having two primary coils 2 and 2*, which are respectively divided into three parts 3, 4, and 5 and 6, 7, and 8, the parts 4, 5, 6, and? be. ing provided with intermediate taps or leads, which are connected to the respective stationary contact-terminals f)v of a reguiating switch 10, the movable member 11 of which is connected to the line conductor 12 of the lsupply-circuit. The other line conductor 13 is connected directly to the outer terminal of the length 8 of the pintary winding of the transformer, and tht .eral lengths nre con nectcd together as follows: the inner terminals of lengths 3 and 8, the outer terminals of lengths 3 and 7, the inner terminals of lengths 4 and 7, and the enter terminals of lengths 4 and 6, and the inner terminals of lengths 5 and 6. lt will be seen that with this arrangement of leads and interconnections the active portion of the primary winding will be symmetrically disposed with refereneeto the secondary winding, here shown as comprising two portions 14 and 15, connected in parallel to the line conductors 16 and 17 when the switcharm 11 is in'engagement with anyV one of the three terminals 9*, 9", and 9.

When the member 11 isin any of its other operative positions, there will be'an unbal- 'anced c \ndition to a limited degree; but this is small 'and may be reduced still further by increasing the number Aof sections into which each coil is divided. As here shown, the ac tive turns of the pri; iary winding are all con-- nected in series, as will be readily seen with- 95,

ont specifically enumerating the conductors which are in the c ircnit corresponding to each position of the regulatingswitch.'

In the modification shown in Fig. 2 the two' secondary coils 14 and 15 of the transformer 1 are connected in parallel to the distribnt l ing-circuit 16-17, the same as in Fig.'1. v The two primary coils 2 sind IS" are also connected in parallel to the supply-mains 12 endlsnd are respectively provided through at lesst n portion of their lengths with spaced lends 1S and 19, the correspondingr leads being crossconnected by conductors 20. The cross-connected leads are connected to thc stationary contact-terminals 21 of a regulating-switch 22, the movable member :23 being adjustable, so ns to vary the active length of the primary winding, and thus vary the voltage ratioof thetransformer. Itwill be resdilyseen that by reason of the symmetrical arrangement of the leads and the cross connectionsthe disposition of the active length of the primary winding with reference to the secondary Winding is always sym metricnl, whatever may be the position of the regulating-switch. This method is practicable and desimblein transformers having but two primary coils; butf the number of coils were greater than two their parallel connection to the supplycircuit might oe impracticsble by reason of the fact that eschcoil would here to be wound for the full voltage ofthe primary circuit. i

In Fig. 3 I have shown a transformer in which the results as regards desired regulation of voltage ratio may be readily secured, whatever may` he the number of primary In this case the secondary coils 14 and 15 of the transformer 1 nre connected in par- :illel'tothe distributing-circuit 1'6 17, thessme its in the preceding figures, and the primary coils 2d vand 2 are respectively divided into two parts 24 25 and 26 27. The part 24 of the coil 2d is provided -With a plurality of spaced leads 24', and the corresponding part 26 ofthe coil 2 is provided in the same manner with a plurality of spaced leads 26". The corresponding leads of the two sets are cross-connected by means of conductors 2,8,

and these cross-connected leads are connected to the stationary contact-terminals 29 bi n regulating-switch 30, the movable member 31 of which is operated to -vary the amount ofnctive winding in the primary circuit of the transformer in a manner which will be readily understood. The portions 24 and of the't'yvo coils 2. and 2 are connected in parallel with each other or corresponding portions of'these sections are so connected, dependin'gof course upon the position of the regulating-switch-30. The portions 25 and 27 of the two coils .are connected in series with each other and are also in series with the active portions ofthe two sections 24 and 26. As an illustration of a result which may be secured with thisA combination and arrangement it maybe'nssumed that two hundred electrical turn'sare required in the primary winding and that it is desired to out ont a totel of one hundred turns in order to secure the msxim'unr'rsnge of voltage variation in the secondary. Such being the case, the sections 24 and 26 may each have one hundred colis is maintained for' all together, as are also the outer torminals'of r turns and the sections 25 and 27 each have titty turns, and since the two sections 25 and 27 are connected in series with -@sich other 7o A hundred turns, nnd'it is also obvious that in 75 this-,method ofconnection the symmetrical relation of the primary coils to the secondary positions of the. regnlstingswitch.

Referring now to Fig. 4, the secondary 8c coils 14 nud 15 of the transformer 1 are connected in parallel to the `distributingoircuit' 16 17,85 in the preceding tiglnre; but the pri mary coils 2f and 2f ere'respectively divided into threc-parts 32, 33, sntiSi and 35,. 36, and 37, the ports 32 and 35 being respective-ly provided with'spsced leads 32* and 35, which are crossconnected by menus of conductors 3S to the stationary contact-ter 9o minnls 39 ol a regulating-switch @fthe movable member 41 of whi h serres to vary the active length of the pr mary winding in sul stnntinlly the manner heretofore described in connection with what is Ashown in the proceding figures. In this modification the outer terminal of the portion 37 of the primary winding is connected directly to the ooudoctor 13 of the supplyinalns. The in ner torrninsls of the parts 34 und 37. are connected the parts 34 and 36. The inner terminals of the parts 33 and 36 are also connected together Iand a supplemental switch 42 is prm vided, one stationary contactfterxninsl-w of which is connected to the outer terminal of the part33, and the otherstaftionary contcb I terminal 44 of which is connected to the outer terminals of the parts v.34 nud 36, the movable member or switch-arm 45 being oon-znected to the inner terminal of the' part 32. 'When the switclisrin 45 is in engagement with'the contact-terminal 43, as indicated in the drawings, the portion'33, 84, 36, and 3.7 l

will be connected in circ'ui tand in 'series with each' other, and either nil or a'psrt of the sections 32 and 35 will be also connected in parallel with each other and in series with the parts 33, 34', 36, and 37, according to the position of the member 41 of the switch-4Q'. When the switch-arm 45 is in engagement-4 and 36 will be ont of circuit and the sections 34 and 37 will be in series with each other and 'alsovin series with such portions of tho sections 32 and 35 es may be connected in parallel circuit with each other by the switch 40. yWhatever may be .the posit-ion of the" switch 42, the active length of the primary winding will obviouslyhe symmetrically da'- posed with reference to the secondary wnddesired result will be secured.

While I have indicated the regnlzjitingly f l means as applied to the primary lWindingcof rac 'with' the contact-terminal 44, the sections. 33

136 ing of the transformer, and consequentlythe y n transformer in ent-l1 of the modifications illustrated .and described, it is toA he under" stood that the desired snlt may be secure-'l by applying the regulating.: means to either the primary or the setondnry winding. I have also shown with trmiormer ns herrin-g only two primary :intl two set-ministry coils; but this illustration lans linen adopted merely to avoid cmplicntion und to .simplify tho illnstratinn and description so far :is nitty be pqssiblv, it boing understood tlmt ordinarily :t vonidornblv number o( both primary iin-d secondary coils is employed n nd that the in.

vention is intended tu he utilizvd in connection with :my number of Stich voila.

Thu illnatrntlon of the invention ns applied tn singlthphnso tmnafurnwrn is nlm 'tint r0- btrictiro. sine@ it is equally npplitnhlo to pulyplmsn trnnsfurmern, nud tht` invnnlitm is to lio construed ns lim-ini; sn'ilicicut cupe to intlmlv trnnsfnrmerx Adapted tu :my number f phases which it may he desirttl to timplny in prnttico.

Ynrintiuns in tlwnrrnngnntcut of tlwspnwd lends und the rugnlntingaswitclies with winrvzitc to cnch otlwr nud also with ruferentn to the sections und circuit connectlonsof tho trnusformnr-cnils may he mndo which nro not hre slwcitiunlly illustrnteil nml which r11-:ry be' found useful in practice. I thorel'nm riunire it tu bo midqrbtuorl that nnynud nll such \nrntiuns which do not mnorinlly modify tlm mudo ntnperntinu or rtsult nru inxzludtd wil hin tht` scopo of my invention.

1. A trnusformor limiupzn plnmlityofcorresponding portions of ono of its windings provided with interconnected loads, ln couibinntion with n switch connected tomdd lends for symmetrically varying the voltage ratio of the transformer.

E` A tmnsformenwinding cnnxpr-ising n plurality 'o-coils nach of which has a pluralitjrof spaced lends, nominations betwepu cob riispo-nding lends of diilerent coils sind a switch for cnnnfecti'ng any set of connect@ 'lends to n lint` conductor.

3. A trnnstonntr having a Awinding: cmuprising n plurality ol coils nach of which hits plurality nt spnnd lends, connections bw tween cnrrespuntling lentlsof ditlem'nt coils,

means for connecting any net o( connected t lends tu n lino cnnductor and n winding: en tnr p'risini: :t plurn'lity o! coils Lxixinectnci in par Anllnl to its lint` conductors.

4. In n transformer, n .winding comprising n plurality of wils n portion of anch uf which' is pros-idw! with 'srmced lends, cnnnections' bntwovn corresponding. tratta of mittlerem vils nud means for connecting :my sul. of connected lends to n linti continctnr in twctirtl-A mme with tim voltage ratio desind.

5. A transformer hln-ing n winding com'- prlslng :t plural-lit)-` o! colla ouch o( which hns ts plurality ol' spaced loads, cnrrisponding loads in thu ditiemut coils being connected permanently in parallel, in combination with n rogulntlngmwitrch having stzitinmtryvcon 

